Abstract: A release lever includes: a release pressing portion pressing a portion around a lock portion of a plate spring to release an engagement of the lock portion with a locked portion; an operation portion located in a front side of the release lever and operated by a lock release operation of an operation handle; and a swing fulcrum portion provided between the release pressing portion and the operation portion. The plate spring integrally includes: a base including the swing fulcrum portion and fixed to an upper rail; a rear biasing portion located behind the base in a vehicle front-rear direction and biasing the lock portion in a lock direction; and a front biasing portion located in front of the base in the vehicle front-rear direction and biasing the operation handle upward. The front biasing portion has a biasing force smaller than that of the rear biasing portion.

Abstract: A release lever includes: a release pressing portion pressing a portion around a lock portion of a plate spring to release an engagement of the lock portion with a locked portion; an operation portion located in a front side of the release lever and operated by a lock release operation of an operation handle; and a swing fulcrum portion provided between the release pressing portion and the operation portion. The plate spring integrally includes: a base including the swing fulcrum portion and fixed to an upper rail; a rear biasing portion located behind the base in a vehicle front-rear direction and biasing the lock portion in a lock direction; and a front biasing portion located in front of the base in the vehicle front-rear direction and biasing the operation handle upward. The front biasing portion has a biasing force smaller than that of the rear biasing portion.

Abstract: A seat reclining apparatus including a base member, a rotatable cover member with an internal tooth gear, three tooth plates with external tooth gears, a pivotable cam member on an inner peripheral side of the tooth plates, a biasing member biasing each of the tooth plates, three guide projections projecting from the tooth plates toward the cover member, an annular grooved portion in the cover member, and three guide surfaces whose one or two being formed on an inner peripheral wall surface of the annular grooved portion, the remainder of the three guide surfaces being formed on the outer peripheral wall surface thereof, wherein the three guide surfaces serve to restrain displacement of the three tooth plates toward the lock position when the respective guide projections are allowed to run upon the corresponding guide surfaces.

Abstract: A seat reclining apparatus including a base member, a rotatable cover member with an internal tooth gear, three tooth plates with external tooth gears, a pivotable cam member on an inner peripheral side of the tooth plates, a biasing member biasing each of the tooth plates, three guide projections projecting from the tooth plates toward the cover member, an annular grooved portion in the cover member, and three guide surfaces whose one or two being formed on an inner peripheral wall surface of the annular grooved portion, the remainder of the three guide surfaces being formed on the outer peripheral wall surface thereof, wherein the three guide surfaces serve to restrain displacement of the three tooth plates toward the lock position when the respective guide projections are allowed to run upon the corresponding guide surfaces.

Abstract: A vehicle seat reclining apparatus comprises a base member to be connected to one of a seat cushion and a seat back, a rotation member which is to be connected to the other of the seat cushion and seat back, which is arranged to rotate relative to the base member and which includes an internal gear, a regulating member to regulate axial movement of the rotation member relative to the base member, and a locking setup which includes an external gear and which is arranged to move between a lock position to engage the external gear with the internal gear and an unlock position for disengagement. The base member includes an outer circumferential portion defining a circular recess, the rotation member includes an outer circumferential portion including a cylindrical portion fit rotatably in the outer circumferential portion of the base member.

Abstract: A vehicle seat reclining apparatus comprises a base member to be connected to one of a seat cushion and a seat back, a rotation member which is to be connected to the other of the seat cushion and seat back, which is arranged to rotate relative to the base member and which includes an internal gear, a regulating member to regulate axial movement of the rotation member relative to the base member, and a locking setup which includes an external gear and which is arranged to move between a lock position to engage the external gear with the internal gear and an unlock position for disengagement. The base member includes an outer circumferential portion defining a circular recess, the rotation member includes an outer circumferential portion including a cylindrical portion fit rotatably in the outer circumferential portion of the base member.